This type of corrugated and perforated sheet is used, for example, in baskets of catalytic reactors designed to promote contact between a catalyst and a product to be treated.
For this kind of application, the sheets have large dimensions, of the order of 13 meters in length by 2 meters in width.
One of the processes used for forming large-sized sheets is explosive forming.
The process comprises the steps of laying the metal sheet on a corrugated die, keeping the metal sheet on the die and creating a vacuum in the space delimited between the said metal sheet and the die.
Next, an explosive charge with remote-controlled firing is arranged on top of the upper face of the metal sheet and the entire assembly is immersed in a firing tank filled with water.
The firing of the explosive charge causes an energy release which has the effect of pressing the metal sheet against the die and thus of forming the corrugations on the metal sheet.
However, the explosive forming of corrugated and perforated sheets poses problems owing to the presence of the perforations which prevent the creation of a vacuum in the space delimited between the metal sheet and the die, so that an air cushion remains between the metal sheet and the die, preventing the metal sheet from being pressed against the die.
To date, a hydraulic press has been used to form corrugated and perforated metal sheets.
Hydraulic presses make it possible to develop large forces, but they are limited to the forming of small-sized sheets because of the constraints imposed by the mechanical elements which make up the presses.